John Lennon ordered Paul McCartney's wife Linda to "shut up" and branded her "insane" in a furious rant after The Beatles broke up.

A series of previously unseen letters penned by the late Imagine hitmaker during the 1960s and 1970s were published on Tuesday to mark what would have been his 72nd birthday.

One note, written in 1971 as the fallout from the Fab Four's acrimonious split the year before reached its peak, displays Lennon's legendary vitriol in full as he takes aim at McCartney and his first wife, apparently in response to a letter from the couple.

On behalf of himself and wife Yoko Ono, Lennon wrote, "I hope you realize what s**t you and the rest of my 'kind and unselfish' friends laid on Yoko and me... We both 'rose above it' - & forgave you two - so it's the least you can do for us - you noble people.

"Linda - if you don't care what I say - shut up! - let Paul write - or whatever... I'm not ashamed of the Beatles - (I did start it all) - but of some of the s**t we took to make them so big - I thought we all felt that way in varying degrees - obviously not. Do you really think most of today's art came about because of the Beatles? - I don't believe you're that insane - Paul - do you believe that?"